No increase in risk of fracture, malignancy or mortality in dermatitis herpetiformis: A cohort study

Background: Dermatitis herpetiformis forms part of the same spectrum of gluten-sensitive disorders as coeliac disease yet may have different risks of morbidity and mortality. Aims: To quantify the risks of fracture, malignancy and mortality in people with dermatitis herpetiformis compared with the general population. Methods: Using the General Practice Research Database, we identified 846 people with dermatitis herpetiformis and 4225 age-, gender- and practice-matched controls. We used Cox regression to estimate hazard ratios. Results: Comparing people with dermatitis herpetiformis to the general population, the overall hazard ratio for any fracture was 1.1 (95% CI: 0.77-1.52). The overall hazard ratio for any malignancy was 1.0 (95% CI: 0.73-1.49); there was no increased risk of gastrointestinal (HR: 1.6; 95% CI: 0.67-3.67) or lymphoproliferative cancers (HR: 1.6; 95% CI: 0.44-6.06). A reduction in risk of breast cancer was not statistically significant (HR: 0.19; 95% CI: 0.03-1.39). The hazard ratio for all-cause mortality was 0.93 (95% CI: 0.70-1.23). Conclusions: Unlike the fivefold increase in risk seen in coeliac disease, we found no increased risk of lymphoproliferative cancer and no increase in fracture, malignancy or mortality in people with dermatitis herpetiformis compared with the general population. It is not clear whether differences in degree of intestinal inflammation or other reasons account for this. Like coeliac disease, dermatitis herpetiformis may protect against breast cancer.